Yes, at first I thought there was a problem with the video, but it was normal on plex-web, so I ruled out the video problem.
Moreover, whether there is a problem with the video or not, it should not cause plex-mac to exit abnormally, so I think there should be an error in plex.
I agree it should maybe just show an error and not crash. It might be playing down it web because the server is transcoding for that client. It is possible to get a copy of the video file I can add to bug report